1. Field of the Invention
This invention relates to a method of determining the quality of wet steam used for enhancing petroleum recovery from a subterranean formation.
2. Description of the Related Art
Steam flooding has become an accepted practice in oil or petroleum recovery from reservoirs that require stimulation to produce a satisfactory flow of crude petroleum. There is a need for a simple method to measure the quality of steam reaching the formation through an injection well. Such a measurement would be particularly useful in determining the amount of heat reaching the underground formation and the cost effectiveness of this type of stimulation.
The measurement of steam quality is of importance since steam quality directly affects production. The quality of the steam which can be most economically injected into a particular reservoir is dependent on a number of parameters. These include the age and hydraulic configuration of the reservoir. It is desirable that the quality of steam injected be adjusted to that quality which best stimulates the well.
The flow rate and quality of injected steam is usually monitored at the choke in the steam injection line. Steam leaves the steam generator at a measured quality pressure and mass flow rate. As the pressurized steam flow progresses toward an injection well, the quality decreases. The decrease is caused by factors as the distance the steam travels, the amount of pipe insulation, and the number and orientation of fittings.
U.S. Pat. No. 4,836,032 to C. L. Redus et al. discloses a method of determining the quality of steam for stimulating hydrocarbon production. The method relies on an orifice plate in series with a critical flow choke.
U.S. Pat. No. 4,681,466 to S. Chien et al. discloses a method of determining the quality of steam. The method makes use of pressure and temperature measurements adjacent two flow restriction means.